1. Field
Percutaneous transluminal therapy.
2. Background
The coronary arteries supply the heart with oxygen-rich blood. When the arteries narrow, less blood and oxygen flow to the heart. The result of narrowing arteries is commonly referred to as coronary artery disease (CAD). Lack of sufficient oxygen to the heart may cause angina or a heart attack. Most cases of CAD are due to atherosclerosis (hardening of the arteries), in which fatty deposits, called plaques, build up inside the coronary arteries, restricting blood flow.
Drug therapy treats stable angina and slows coronary artery disease progression. Unstable angina may require surgical intervention in addition to the therapies given for stable angina.
To date, surgery is usually recommended for patients who have unstable angina that does not respond promptly to medical treatment, who have severe recurrent episodes that last more than 20 minutes, or who have other high risk factors for heat attacks. Surgery is also typically performed in people with severe coronary artery disease (e.g., severe angina, multi-vessel involvement, evidence of ischemia), particularly if abnormalities are evident in the left ventricle of the heart.
A number of invasive techniques are available for treating coronary artery disease. Two standard surgical procedures are coronary artery bypass grafting and percutaneous transluminal coronary angioplasty (PTCA). Studies have generally reported similar effectiveness in the two procedures, although one or the other may be preferable for specific patients. Angioplasty is less invasive than bypass and initially less expensive, although the post-operative need for medications and the high risk for repeat procedures to reopen the artery reduce the long term difference in cost. With the introduction of drug-eluting stents (DESs), the risk of repeated procedures is significantly lowered. However, bypass is still preferred for certain patient groups. For example, it is generally recommended for patients with three or more blocked arteries, or where the left main artery is narrowed by 50 percent or more, or when the diseased portion of the artery is very long. Patients with diabetes used to have a significantly better long term survival rate with bypass surgery than with angioplasty, but this difference is much offset by DES.